The mother of a mentally ill inmate who died after sexually mutilating himself in a Rikers Island cell slapped the city Wednesday with a wrongful-death lawsuit alleging guards there drove him to his grisly death by denying food, water and medical care for seven straight days.

Bradley Ballard’s mother, Beverly Ann Griffin, claims in the Manhattan federal court wrongful-death lawsuit that corrections officers and medical staff “essentially stood by and watched” as her 39-year-old son “languished, deteriorated, and ultimately died.” She also says their actions are part of a longstanding practice of “abhorrent” mistreatment of Rikers’ prisoners, which also includes another inmate who “baked to death” in his overheated cell in February.

“The number of times correctional staff, medical personal and other staff passed by Mr. Ballard’s cell while he was in dire circumstances during these seven days — doing nothing to assist or aid him — shocks the conscience,” the suit says.

Ballard, who was a diagnosed schizophrenic and diabetic, was confined to his cell in a mental observation unit for making a lewd gesture at a female guard.

The suit – which names former Corrections Commissioner Dora Schriro and others as defendants – alleges guards regularly strolled by her son’s cell and did nothing, even though he was weak, collapsed, naked and covered in his own feces and vomit. His meds were withheld and a nurse only visited him once over the week he was confined.

A recent report by Manhattan US Attorney Preet Bharara called Rikers Island a “broken institution.”AP

“Unable to endure the stress of his situation, and with his schizophrenia unmediated, Mr. Ballard engaged in self-mutilation, taking off all his clothes and tying a rubber band around his genitals,” says the suit.

Rikers Island has come under fire in recent months. Manhattan US Attorney Preet Bharara compared it to the 1954 novel “Lord of the Flies” in August by calling it a “broken institution” run amok with excessive force by guards and a place where the rights of teenage inmates are routinely violated.

Prosecutors are investigating Ballard’s death, which the medical examiner ruled a homicide.